Unloading device for compressors.



H. W. CHENEY.

UNLOADING DEVICE PoR ooMPREssoRs.

APPLICATION FILED MAY 27, 1912.

Patented Mar AT1-:IHN EY.

` INQENTDQ- WITNEESEE nns'rarns rarnnr oratori. A'

emnnnn'r. W. CHENEY, or ramwaonnnfwrsoonsrn, assrenon, nr Mpenza aesinet menus, 'ro ALMS-onenrrnns mnnueec'ronne COMPANY, n conronerron on nnnawnnn,

maaien? 'To all 'whomz't' may conomt'i .l I- I Beit known that HnniannrW-...Gmnnm a 'citizen of' the 4United Sttes,^.residing at Milwaukee, in the county ci 'lvlwaukee 'and State of Wisconsin, have invented'acertaln new and useful Improvement in Unloading Devices for Compressors, of whichzthefollowingisa specication.` :,llhis invention relates 'to unloading dej vicesffforfcompressors, and particularly to suohdevic'ea as may be applied Ito unload an electric motor used to drive a' compressor, andespeciall'y. `such Ielectric motors whose sta/ rtirgftorque is 'lo'wr The object of the invention is to provide a simple and efficient means whereby the motor driving the compressor is allowed to attain nearly full speed before the load is thrown in. The device is. entirely automatic after once being adjusted, and is designed as an improvement over the unloadingdevice of Patent No. 995,401, June 13, 1 9 1 1. N in said patent there is a continuous leakage) of" air through the. smallleak-off portvvhe n the 'compressor is inaction. 'This is' objectionable and is entirely prevented in the present invention. l: A clear conception of the invention can be had by referring to the accompanying draw- `:String in which like reference characters'desig-l nate the samepart in the different views. in, the drawing-Figure 1 is an enlarged longitudinal -sectional view of the device. Fig..2-is an'end-elevation, also enlarged, as viewed from the left in Fig. 1. Fig. 3 is a reducedschematic 'view of the ,device showingits relation to thecompressor-and to the receiver. v

Referring to the drawings, especially Fig. 40 3, the compressor 30 is connected to the receiver 40 through the connection 1, embody.

ing the unloading device, by means of ordinary end usual piping.

Referring more especially to Fig.' 1 of the drawing; the-connectionn1-forms a casing havingan inlet -101a'n'dz 'anoutlet 9.- A

ported partition 31 separates the inlet'space 4: from the outlet space-7, and 'the port in the partition 31 is controlled by a springpressed Valve 6, the spring 8 of which reacts against a cap 3 screwed'into the top of the' casing forming' the connection 1.. This `valve 6 therefore comprises a checkvalve to prevent the return of air from the receiver.

'will the bottom of the inlet spaced is formed "momma Dnvrcn non. conrnnssons.

Specmcation of Letters Patent. Patented lidar'. Sil), 1915s i application area may at', 1era .serial no. accesa.

a projection which is bored through to the outside, the bore beingA closed by the plug 25 which is locked in place by the nut 24. The bore has a cored by-pass 11 opening to atmosphere through-the bottom of the casce ing. At the upper end of the bore through the projection, is formed a valve seat .or the valve 5 held open against the cap 2 screwed in the top of the casing forming the connectlonl, bymeans of a spring 13 re- 65 at'zti'ng''with in` a recess in the plug 25. A.

small pc'rt' 12' is formedjin the projection connecting. the 'inlet space 4 with the through bre formed in the projection. lt will thus beseen that `the inlet space 4 may 70 be connected t'o'- atmosphere through two ports andthe comnior1'-bypa's's 11.

- The connection 1 has a necked portion betweenthelinlet) 10 andthe inleti space which isr bored out' and ifi' which' loosely 75 fitted a plunger 1 8 having yfour space wings 19 .which guide the plunger Iwithin.V the bore of the 'necked portion. A' pin f22'1having a threaded shank and head 2 3', is screwed into the connection 1 in position toiorm l'a stop 80 for the plunger 18 to prevent its withdrawal from the connection 1. A sprinfll'jacting against a nut 16 screw-threade L lipon the reduced inner` end of the plunger V 18 and heldin place thereon by lock nuts 1'?, tends 85 to hold' the plunger 1,8 in` contact `with the stop-pin'22.- The spring 15v reacts against the 'projectioniri thel bottom of 'the' inlet space fi. I tyshould'beunderstood, 'that by the1-useof the termspringis included any 90 equivalent such as gravity orair pressure means",

' -The plunger18 is axially. bored through and o'unterbored at its outer end. A valve 14- proje'ctsfrom the front end of the plun- 95 ger and-has a head 82 located within the counterbore to limit the extent of projection of thel valve 14: from the plunger 18. A

spring 20 lies within the counterbore of the plunger 18 and acts against the head 32 of 100 the valve 14 while reacting. against a screw plug 21 closing the outer end of' the counterbore. `'.'lhe valve'l coacts with'the valve seat formed at the inlet space end 'of the port 12. It will thus be seen that-there is a lost motion connection between the valve 14: andthe plunger 18, the spring within which tends to hold the valve 14 in a definite position with respect to said plunger.

The operation is asollows'f 'Assuming- 1l@ thecoinpressor to be inactive, the 'valves' and 14will be off their respective seats, the

springs 13- and 15 respectively holding them tween the wings 19 ofl theplunger will at once carry the plunger to the right, referring to Fig. l, against the increasing compression of spring 15 until the valve 14 closes off the port 12. It will even continue :farther than this in its travel and compress the spring 20,' leaving the valve 14 in its closing position. The air inthe inlet space 4 will become compressed and will leak past valve 5 through the bore and by-pass ll to atmosphere, thus unloading the conipressor.` At about the time the motor has attained full speed, the increasing pressure in inlet space 4 will close valve 5 against its spring 13 and shut off the relief port to atmosphere. The compressed air will then unseat the valve 6 in the partition 31 against its spring 8 and flow through the outlet 9 to `the receiver 40. A

After the receiver is under due compres sion the motor will be s opped in any desired manner, after which he plunger 18 will move to the left by action of spring 15 and.

finally unseat the valve 14. This will at once relieve the inlet space 4 through port 12, the bore and by-pass 11, after which the A valve 5 also will be unseated by action of the spring 13. The device will then be ready for the next startin of the compressor.

It should be note that the pulsations that may be present during the action of the compresser are free ,to vibrate the plunger 18' back and forth to some extent without disturbing the closed condition of valve 14. This is dueto the lost motion spring connection between the valve 14 and the plunger .18. -The same connection prevents shock during the seating of valve 14. It should also be noted that the weight of the plunger 18 constitutesa timing element that prevents the quick action, or rather the too quick action, of the valve 14, as it takes time to accelerate a heavy body such as the plunger18.

It should be understood that it is not desired to be limited to the exact details of construction shown and described, for obvious modifications will occur to a person skilled in the art.

'It is claimed and desired to secure by Letters Patent,- l

1. In an unloading device for compressors, the combination of a casing having a springopened-valve-controlled outlet to atmosphere, a check valve controlled outlet to the receiver, .a relief port to atmosphere, and a spring-opened valve controlling said relief port.

2. In an unloading device, a compressor, a

receiver, a connection between said compresinsegna sor andsaid receiver said connection having a plurality of ports connecting to atmossor'and said receiver, a spring-closed valve in said connection, said connection having between said compressor andl said valve a plurality of ports connecting to atmosphere, a valve adapted'to be closed by pressure'in' said connection for controlling one ofsaidports, and a valve adapted to beclosed by How of air from said compressor into said connection for controlling'the other of said ports.

4. In an unloading device, a compressor, a receiver, a connection between said compressor and said receiver, a spring-closed valve in said connection, said connection having between said compressor and'said valve a plurality of ports connecting to atmosphere, a second valve adapted to beclosed by pressure in said connection for controllin one of said ports, a third valve controllingt e other of said ports, a plunger adapted to be moved by flow of air into said connection to close said valve, and a spring between said third valve and said plunger compressible during said movement of said plungerto close said valve. r

5. In an unloading device, a Compressor, a receiver, a connection between said compressor and said receiver, two relief ports to atinosphere from said connection, a springopened valve for one of said ports closable by an excess of connection. pressure over atmospheric pressure, a plunger, a valvefor the other o f said ports, a spring between said plunger and said second valve, said pluger being movable by'an excess of compressor pressure over connection pressure to close said second valve throughsaid spring, and a spring for' returning said plunger to openV sor and said receiver, two relief ports to atmosphere from said connection, a springopened valve for one of said ports closable by an excess of connection pressure over at,- mospheric pressure, a plunger loosely fitting the inlet to said connection and adapted to be moved by the flow of air into said connection, a spring for returning saidplunger after cessation of said iiow, a valve for said second port having a lost-motion connection with said plunger, and a spring tending to hold said second valve in a definite positionv with respect'to said plunger, said second valve closing said port during said flow.

7 In an unloading device, a compressor, a receiver, a connection between said compressor and said receiver, a valve controlling a relief port from said connection to atinos- Libere, means actuable to close said valve by inventor is ailixed hereto in the presence of ow of air from said com ressor into said tvvo witnesses.

connection, Vspring means or opening said HERBERT W; 'CI-IEY. valve, and means for delaying the opening Witnesses: v v of seid` valve. l Cms. L. BYRON,

In testimony whereof, the signature ofthe G. F. Dn WEIN. 

